Reprap Full Graphic Smart Controller starts beeping and flashing backlight

Hi all,

suddenly the RepRap Full Graphic Smart Controller Board on my Fabricator Mini 1.5 started to flash the backlight and beep in roughly a one second rhythm. A few minutes earlier it was still working. Since it worked before and the cables on both sides have keyed connectors, I can rule out that the cables are connected wrong.
The only thing I noticed before the failure was that the display itself was showing a low contrast section in the middle of the display that has appeared there a while ago and the backlight might have been a little bright.
What could cause this?

Best regards,
Reiner

5v voltage regulator on the megs is dying/dead

If you plug in USB it will probably bypass it and work. but is not a long term solution.

Pluging in USB did not help. With the display disconnected, I measure 4.9V between pin 9 and 10 on EXP1. If I connect the display, the voltage drops to ~0.5-07V.
The board is a MKS Base V1.3. Is there anything I can check before extracting the whole mainboard?